AD9762
–6–
REV. B
DEFINITIONS OF SPECIFICATIONS
Linearity Error (Also Called Integral Nonlinearity or INL)
Linearity error is defined as the maximum deviation of the
actual analog output from the ideal output, determined by a
straight line drawn from zero to full scale.
Differential Nonlinearity (or DNL)
DNL is the measure of the variation in analog value, normalized
to full scale, associated with a 1 LSB change in digital input
code.
Monotonicity
A D/A converter is monotonic if the output either increases or
remains constant as the digital input increases.
Offset Error
The deviation of the output current from the ideal of zero is
called offset error. For I
OUTA
, 0 mA output is expected when the
inputs are all 0s. For I
OUTB
, 0 mA output is expected when all
inputs are set to 1s.
Gain Error
The difference between the actual and ideal output span. The
actual span is determined by the output when all inputs are set
to 1s minus the output when all inputs are set to 0s.
Output Compliance Range
The range of allowable voltage at the output of a current-output
DAC. Operation beyond the maximum compliance limits may
cause either output stage saturation or breakdown resulting in
nonlinear performance.
Temperature Drift
Temperature drift is specified as the maximum change from the
ambient (+25°C) value to the value at either T
MIN
or T
MAX
. For
offset and gain drift, the drift is reported in ppm of full-scale
range (FSR) per degree C. For reference drift, the drift is
reported in ppm per degree C.
Power Supply Rejection
The maximum change in the full-scale output as the supplies
are varied from nominal to minimum and maximum specified
voltages.
Settling Time
The time required for the output to reach and remain within a
specified error band about its final value, measured from the
start of the output transition.
Glitch Impulse
Asymmetrical switching times in a DAC give rise to undesired
output transients that are quantified by a glitch impulse. It is
specified as the net area of the glitch in pV-s.
Spurious-Free Dynamic Range
The difference, in dB, between the rms amplitude of the output
signal and the peak spurious signal over the specified bandwidth.
Total Harmonic Distortion
THD is the ratio of the rms sum of the first six harmonic
components to the rms value of the measured output signal. It is
expressed as a percentage or in decibels (dB).
Multitone Power Ratio
The spurious-free dynamic range for an output containing mul-
tiple carrier tones of equal amplitude. It is measured as the
difference between the rms amplitude of a carrier tone to the
peak spurious signal in the region of a removed tone.
50pF
COMP1
+1.20V REF
AVDD ACOM
REFLO
COMP2
PMOS
CURRENT SOURCE
ARRAY
0.1F
+5V
SEGMENTED SWITCHES
FOR DB11–DB3
LSB
SWITCHES
REFIO
FS ADJ
DVDD
DCOM
CLOCK
+5V
R
SET
2k⍀
0.1F
DVDD
DCOM
IOUTA
IOUTB
0.1F
AD9762
SLEEP
50⍀
RETIMED
CLOCK
OUTPUT*
LATCHES
DIGITAL
DATA
TEKTRONIX
AWG-2021
LECROY 9210
PULSE GENERATOR
CLOCK
OUTPUT
50⍀
20pF
50⍀
20pF
100⍀
TO HP3589A
SPECTRUM/
NETWORK
ANALYZER
50⍀ INPUT
MINI-CIRCUITS
T1-1T
* AWG2021 CLOCK RETIMED
SUCH THAT DIGITAL DATA
TRANSITIONS ON FALLING EDGE
OF 50% DUTY CYCLE CLOCK.
Figure 2. Basic AC Characterization Test Set-Up
